Move assert.h/assert.cc from runtime/vm to runtime/platform

runtime/bin/directory.cc

-// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
+// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-#include "bin/dartutils.h"
 #include "bin/directory.h"
 
+#include "bin/dartutils.h"
 #include "include/dart_api.h"
+#include "platform/assert.h"
 
 static intptr_t GetHandlerPort(Dart_Handle handle) {
   if (Dart_IsNull(handle)) {
     return 0;
   }
   return DartUtils::GetIntegerInstanceField(handle, DartUtils::kIdFieldName);
 }
 
 
 void FUNCTION_NAME(Directory_List)(Dart_NativeArguments args) {
@@ skipping 102 matching lines @@
   Dart_EnterScope();
   Dart_Handle path = Dart_GetNativeArgument(args, 0);
   if (Dart_IsString(path)) {
     bool deleted = Directory::Delete(DartUtils::GetStringValue(path));
     Dart_SetReturnValue(args, Dart_NewBoolean(deleted));
   } else {
     Dart_SetReturnValue(args, Dart_NewBoolean(false));
   }
   Dart_ExitScope();
 }